Fog in a Bottle
demonstrationactivity exercisesuggested grade levels: 6- 8

view Idaho achievement standards for this lesson

Fog is a cloud near the ground, produced by warm air coming in contact with cool air. Since cool air cannot hold as much moisture as warm air can, the moisture condenses in the form of tiny droplets and this results in fog. You can create your own fog if you follow the instructions below.

1. Students will learn about basic concepts such as evaporation, condensation, and relative humidity.
2. Students will become exposed to the Digital Atlas of Idaho.

clear bottle ice
hot water Isopropyl alcohol

Use the cloud imaging section of the Digital Atlas of Idaho. To get there: Click on Atlas Home, Climatology, then on Cloud Imaging. Scroll down and read the section on and learn about the many different types of fog. This should serve as an excellent review before doing this activity. You may also wish to review the relative humidity, condensation, and evaporation sections if you are not familiar with these topics.

Review as a class:
-Relationship of relative humidity with temperature
These concepts are important to review because the students must understand them in order for the students to understand the following activity. When doing the following activity, have the students try to predict what should happen at each step along the way.

Fill a bottle one-third full of very hot water. Add a few drops of isopropyl alcohol. Alcohol vaporizes rapidly, letting you see the fog form more quickly. Place a piece of ice over the bottle mouth. Observe what happens near the neck of the bottle.

Questions for class discussion:
1. What happened to the relative humidity as the air cooled near the top of the bottle?
2. What caused the condensation you observed?
3. Could this also be how fog and clouds form?
4. Would you expect to see fog at cooler temperatures or higher temperatures?

Handouts/Activity links:
These are links to access the handouts and printable materials.
Cloud Imaging

Related Lesson Topics:
Climatology: Climatology

Lesson plan by Dr. Helen Challand and Elizabeth Brandt with permission from Science Activities from A to Z, 2001
Idaho Achievement Standards (as of 7/2001) met by completing this activity: